1. Field of the Invention
The present invention relates to a socket for an electrical part for detachably accommodating an electrical part such as a semiconductor device (called as xe2x80x9cIC packagexe2x80x9d hereinafter), and more particularly, to a socket for an electrical part provided with a guide member or unit for guiding the electrical part to a predetermined position at a time of the accommodation thereof.
2. Related Prior Art
As a conventional xe2x80x9csocket for electrical partsxe2x80x9d of this kind, there is provided an IC socket for detachably accommodating an IC package as xe2x80x9celectrical partsxe2x80x9d. This IC package is preliminarily set on a printed circuit board such that the IC package and the printed circuit board are electrically connected when the IC package is accommodated in the IC socket.
The IC package includes, for example, an LGA (Land Grid Array) type of IC package which has a rectangular-shape package body and a large number of plate-shaped electrodes as terminals mounted on a bottom surface of the package body.
On the other hand, the IC socket is provided with a number of contact pins, and the contact pins have upper contact portions, in an installed state, which contact the plate-shaped electrodes in a state that the IC package. is accommodated in the IC socket to thereby establish an electrical connection between the respective plate-shaped electrodes of the IC package and the printed circuit board through the contact pins, respectively.
One example of such structure, in which the IC package is easily aligned with the IC socket, is shown in the publication of U.S. Pat. No. 6,164,980. This known structure is provided,. as shown in FIG. 17, with first, second, third and fourth wall sections 116, 118, 120 and 122, which define a rectangular opening area for accommodating an IC package 126. The first wall section 116 is formed with a pair of elastic pieces 134 and 136 for applying first forces 142 and 144 to the IC package 126. Similarly, the second wall section 118 is also formed with a pair of elastic pieces 138 and 140 for applying second forces 146 to the IC package 126.
Furthermore, the third and fourth wall sections 120 and 122 are formed with contact points 128, 130 and 132, each having an outward protruded shape, which contact to the IC package 126.
According to the structure of FIG. 17 mentioned above, the IC package 126 is positioned through the forcible contact of the contact points 128, 130 and 132 by means of elastic pieces 134, 136, 138 and 140.
In such known structure, however, the IC package 126 is positioned, with reference to the contact points 128, 130 and 132 of the wall sections 120 and 122, by forcibly contacting (pressing) the IC package 126 to these contact points. Therefore, in a case where any error during the formation of the IC package 126 occurs, it is difficult to accord the center of the IC package 126 with the center of the accommodation of the IC package 126, and moreover, in a case where the IC package 126 is accommodated in a state shifted in position towards the sides of the wall sections 120 and 122, there is a fear that the IC package 126 may ride on the wall sections 120 and 122 and is hence not surely accommodated in the predetermined position.
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art described above and to provide a socket for electrical parts having a structure in which the center of the electrical part surely accords with the accommodation center thereof, and even if the electrical part is shifted in position at the accommodation thereof, the electrical part can be smoothly accommodated.
This and other objects can be achieved according to the present invention by providing a socket for an electrical part, which is provided with a socket body for accommodating an electrical part having a body having a surface to which an electrode is formed, and in which a guide member is provided for the socket body so as to guide side surfaces of the body of the electrical part at the time of the accommodation of the electrical part and the socket body is formed with a number of contact pins so as to be contacted to or separated from the electrode of the electrical part,
wherein the guide member includes a plurality of guide portions disposed so as to correspond to the side surfaces of the electrical part body, respectively, each of the guide portions elastically pressing inward the side surfaces.
According to this structure, since the guide portions of the guide member are arranged for elastically pressing the respective side surfaces of the electrical part body, the electrical part can be guided to its predetermined position even if the electrical part is offset in any direction at the time of the accommodation. Furthermore, as mentioned above, since the respective side surfaces of the electrical part body are elastically pressed by the guide portions, the electrical part is subjected to the centering operation within the insertion area thereof and the center of the electrical part can surely accord with the center of the insertion area thereof.
In preferred embodiments of the above aspect, each of the guide portions is formed with an elastic piece which is elastically deformable and a pressing portion formed to a front end of the elastic piece, in which the pressing portion abuts against the side surface of the electrical part body so as to press the side surface thereof by an elastic force of the elastic piece.
At least one of the guide portions is arranged to one side surface of the electrical part body and at least other two guide portions are arranged to another side surface opposite to the one side surface across the electrical part body, the other two guide portions also being each disposed along the long direction of the another side surface and at each both outside portions, of the another side surface, from a position opposite to the one of the guide portions across the electrical part body.
Another aspect of the present invention is that one of the guide portions is arranged to one side surface of the electrical part body and other two guide portions are arranged to another side surface opposite to the one side surface across the electrical part body, the other two guide portions also being each disposed along the long direction of the another side surface and at each both outside portions, of the another side surface, from a position opposite to the one of the guide portions across the electrical part body.
And a plurality of guide portions can be at least arranged to one of the side surfaces.
Still another aspect of the present invention is that at least one of the guide portions is arranged to each of both outside portions, from a central portion and along the long direction, of one of the side surfaces of the electrical part body, and at least other two guide portions are each arranged to another side surface of the electrical part body opposite to the one of the side surfaces thereof at each position opposite, across the electrical part body, to boss of the guide portions arranged to the one of the side surfaces so that the electrical part body is clamped between the guide portions arranged to the one of the side surfaces and the guide portions arranged to the another side surface.
Still another aspect of the present invention is that a socket for an electrical part according to claim 1, wherein two guide portions is each arranged to each of both outside portions, from a central portion and along the long direction, of one of the side surfaces of the electrical part body, and other two guide portions are each arranged to another side surface of the electrical part body opposite to the one of the side surfaces thereof at each position opposite, across the electrical part body, to the two guide portions arranged to the one of the side surfaces so that the electrical part body is clamped between the two guide portions arranged to the one of the side surfaces and the other two guide portions arranged to the another side surface.
And a plurality of guide portions can be at least arranged to one of the side surfaces.
The guide portions are formed to respective sides of a frame member having a central opening having a size suitable for accommodating the electrical part, therein, the frame member being mounted, to be detachable, to the socket body.
According to the above preferred embodiments of the present invention, since the guide member is formed of the elastic piece having the front end to which the pressing portion is formed, the guide member can be easily formed through an integral formation of such as resin material.
Furthermore, since the guide portion is formed with the elastic property, any force to rotate the electrical part with respect to the area in which the electrical part is accommodated can be prevented from causing, and the electrical part can be hence smoothly guided and stably accommodated.
Still furthermore, since the electrical part can be supported by equal forces applied from a plurality of directions, the electrical part can be further smoothly guided and accommodated.
Even in a case where a plurality of electrical parts having different outer shapes are to be accommodated, it is not necessary to change the socket body by preparing a plurality of frame structures having difference central openings corresponding to the electrical parts, respectively.
In a modified aspect of the present invention, there will be provided a socket for an electrical part comprising:
a socket body for accommodating an electrical part having a body having a surface to which an electrode is formed;
a guide member having a frame structure provided for the socket body for guiding a side surface of the electrical part body at a time of the accommodation of the electrical part; and
a number of contact pins provided for the socket body so as to be contacted to or separated from the electrode of the electrical part,
the guide member including a plurality of guide portions disposed at side portions of the frame structure thereof so as to correspond to the side surfaces of the electrical part body, respectively, each of the guide portion having an elastic portion to press inward the side surface of the electrical part body.
According to this modified aspect, substantially the same function and effect as that mentioned above will be achieved.